This invention relates to the deployment of inflatable structures, and more particularly to a pressurized actuator system that utilizes pneumatic or hydraulic force for initiating the reliable rapid deployment of inflatable structures and/or the simultaneous deployment of multiple inflatable structures.
Certain types of aircraft, such as commercial fixed wing aircraft and rotorcraft such as for example, helicopters, are required by the regulatory agencies to carry inflatable floatation devices for passenger safety in the event of an emergency situation over water. Fixed wing commercial aircraft, for example, typically include one or more inflatable slides that are normally stored uninflated in a container mounted on the interior of the aircraft door or immediately adjacent thereto. With the door closed, a girt bar is connected to brackets on the floor inside the doorway such that it is only necessary to open the door to automatically deploy the slide in the event of an emergency evacuation. When the door is opened, the girt bar normally pulls the slide through the doorway until gravity can take effect to unfold or unroll the slide outside of the doorway. Once outside the doorway, the slide or slide/raft is rapidly inflated through the application of fluid pressure.
In military applications, inflatable life rafts and their inflation systems are sometimes located in external compartments of the aircraft in order to maximize space in the fuselage for transporting equipment, supplies and personnel. Multiple life rafts and their inflation systems may be located in the external compartments. The inflation system for each life raft includes a container of pressurized gas with an inflation valve that can be actuated from a remote location, such as the cockpit, by mechanical means which may be in the form of a cable and pulley system routed through the aircraft. When a pull handle or similar device associated with the system is activated, the valve is opened and the pressurized gas is discharged from the container and into the life raft causing its rapid inflation. Some of such inflation systems employ a secondary applied force for discharging a secondary pressurized fluid to indirectly activate the primary inflating system. An example of such systems has been disclosed in U.S. Pat. No. 6,644,596. It should be noted however that such prior art deployment systems are typically adapted for deployment of a single inflatable structure and not necessarily concentrated simultaneous deployment of multiple inflatable structures.
Mechanical inflation systems for rotorcrafts have also been employed in order to enable the rotorcraft to land on water in an emergency situation, such as when the rotorcraft loses power. Such systems provide passengers with extra crucial time to escape before the rotorcraft sinks. The inflation system typically includes multiple emergency flotation devices mounted to the rotorcraft landing gear, a container of pressurized gas for each floatation device, an inflation valve associated with the pressurized container, and a mechanical system routed through the helicopter for actuating the inflation valves. It is essential that all floatation devices are simultaneously deployed to ensure rotorcraft stability, especially as it lands on the water. Unbalanced deployment of the floatation devices could cause the rotorcraft to capsize and prevent the quick escape of passengers. In addition, when an emergency situation occurs at relatively high speeds, such as 120 knots, simultaneous deployment of the floatation devices ensures that the flying characteristics of the rotorcraft will not be unbalanced. Thus, great care must be taken to ensure that the cables are properly sized, sufficiently taut, lubricated, and in good working order so that the floatation devices may be simultaneously deployed.
However, during aircraft maintenance procedures, the cables and pulleys may be painted over and not properly tested and lubricated for movement on a regular basis. Corrosion and debris can also restrict or resist cable movement. Consequently, higher and unequal pull forces may be required to activate the inflation systems. The unequal pull forces may cause only one float to be deployed or cause a highly undesirable delay between the deployments of both floatation devices.
Although other systems or mechanisms can be used for simultaneously deploying the floatation devices, they have their own disadvantages. By way of example, an electrical system might employ a solenoid valve that is actuated upon supplying a voltage. Likewise, a pyrotechnic mechanism uses an explosive charge inside the valve for its activation. However, when an emergency landing situation occurs due to a loss of rotorcraft power, the emergency flotation devices may not be deployed since there may not be enough electrical current to actuate the solenoid valve or set off the explosive charge.
It would therefore be desirous to provide an actuator system that eliminates the requirement for cable and pulley systems as well as electrically powered mechanisms. It would be further desirous to provide an actuator system that ensures the simultaneous deployment of multiple flotation devices.